[Paraview] Question about Integrate Variables Filter

[Yuanxin Liu]

Hi, Sam & Magician,
   These are good ideas and we will definitely improve these functions as
you suggested.

   I have opened bug reports to keep track:
   - http://vtk.org/Bug/view.php?id=13235 for the quad integration
   - http://vtk.org/Bug/view.php?id=13234  for the temporal statistics

   If you manage to implement fixes before we get to it,  please feel free
also to post your solution and we will try to incorporate them into the
repository.

thanks,

Leo

On Mon, Jun 11, 2012 at 11:18 AM, Magician <f_magician at mac.com> wrote:

> Hi Leo & Sam,
>
>
> Thanks for your replies.
> The bilinear integration method which Sam wrote was just I intended.
> I could open the PDF document on Mac OS X and iOS (iPhone/iPad).
>
> Additionally, I found a similar problems on Temporal Statistics filter.
> I prepared two transiend data sets.
>
> > Case 1:
> > t=1.0, scalar=1
> > t=2.0, scalar=2
> > t=4.0, scalar=4
> >
> > Case 2:
> > t=1.0, scalar=1
> > t=1.1, scalar=2
> > t=4.0, scalar=4
>
> Both Temporal Average Values are 2.3333.
> And if I apply Temporal Interpolation filter and Temporal Statistics
> filter again,
> there are different results.
> The reason is the Temporal Static filter is just calculating sum average,
> and transient time values are not considered.
>
> I'd like to get time-weighted average values by Temporal Statistics filter.
>
>
> Magician
>
>
> On 2012/06/11, at 9:36, Yuanxin Liu wrote:
>
> > Hi, Sam,
> >   Would you mind reposting this?  The pdf file seems corrupt.
> > thanks,
> > Leo
> >
> > On Sun, Jun 10, 2012 at 7:38 PM, Samuel Key <samuelkey at bresnan.net>
> wrote:
> > Hi Leo,
> >
> > Though likely more arithmetically intense than you would like, I have
> attached a 3-page write-up on how to do an exact integration over the
> surface of a bi-linear isoparametric coordinate based quadrilateral in
> three-space. It is easily adapted to a flux integration as well.
> >
> > If it helps, please free to incorporate it into ParaView.
> >
> > Sam Key.
> >
> >
> >
> >
> > On 6/10/2012 12:55 PM, Yuanxin Liu wrote:
> >> Hi,
> >>    This is not really a bug, but just what the linear precision
> integration does.  As you can see in vtkIntegrateAttributes.cxx:215, the
> quad cell is basically cut into two triangles along a diagonal, integration
> is done for each triangle and the results are added up.   So, depending
> where your "1" falls on a diagonal vertex, you will get different results.
> >>
> >> Leo
> >>
> >>
> >> On Sat, Jun 9, 2012 at 8:57 AM, Magician <f_magician at mac.com> wrote:
> >> Hi all,
> >>
> >>
> >> Now I found a bug of the filter.
> >>
> >> My ParaView's version is 3.14.1.
> >> I define node names as below:
> >> > c--d
> >> > |  |
> >> > a--b
> >>
> >> Case 1: a=1.0, b=0.0, c=0.0, d=0.0
> >> Integration Value = 0.33333
> >>
> >> Case 2: a=0.0, b=1.0, c=0.0, d=0.0
> >> Integration Value = 0.16666
> >>
> >> Case 3: a=0.0, b=0.0, c=1.0, d=0.0
> >> Integration Value = 0.16666
> >>
> >> Case 4: a=0.0, b=0.0, c=0.0, d=1.0
> >> Integration Value = 0.33333
> >>
> >> So Integration Values are calculated as (2*a+b+c+2*d)/6.
> >> I think it's not a good result.
> >>
> >>
> >> Magician
> >>
> >>
> >> On 2012/06/08, at 12:54, Magician wrote:
> >>
> >> > Hi all,
> >> >
> >> >
> >> > I'm now comparing integration results of each postprocessors.
> >> > I made a simple Quadratic VTK model as below:
> >> >> # vtk DataFile Version 2.0
> >> >
> >> >> QuadCell
> >> >> ASCII
> >> >> DATASET UNSTRUCTURED_GRID
> >> >> POINTS 4 FLOAT
> >> >> 0 0 0
> >> >> 1 0 0
> >> >> 0 1 0
> >> >> 1 1 0
> >> >> CELLS 1 5
> >> >> 4 0 1 3 2
> >> >> CELL_TYPES 1
> >> >> 9
> >> >> POINT_DATA 4
> >> >> SCALARS scalar FLOAT 1
> >> >> LOOKUP_TABLE DEFAULT
> >> >> 0.0
> >> >> 1.0
> >> >> 2.0
> >> >> 4.0
> >> >
> >> > When I apply Point Data to Cell Data filter,
> >> > scalar values are interpolated as 1.75.
> >> > It may be calculated as (0.0+1.0+2.0+4.0)/4.0.
> >> >
> >> > But when I apply Integrate Variables filter,
> >> > scalar value is integrated as 1.833....
> >> > The area value of quadratic cell is 1.0, so I thought
> >> > integrated values should be equal to cell data.
> >> >
> >> > How the integrated value is calculated?
> >> >
> >> >
> >> > Magician
>
>
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